glibc 2.41 backport treats more DNS RR types as unknown

A glibc 2.41 stable backport changes the DNS resolver’s resource-record pretty-printer so that CERT, TKEY, TSIG, and OPT records are handled as unknown types rather than with dedicated formatting logic.

The update removes the incomplete and buggy TSIG printer, which addresses CVE-2026-5435 along with an internal bug report on that path, and partly clears a related report covering other record types. Callers that format resolver output no longer exercise the old type-specific code for those records.

Florian Weimer authored the upstream change; Jaipaul Cheernam carried the 2.41 backport, reviewed by Carlos O'Donell and Adhemerval Zanella.